@keyframes slide {
    0% {
        margin-left: 0;
        /* transform: translateX(0); */
    }

    50% {
        margin-left: 200px;
        /* transform: translateX(200px); */
    }

    100% {
        margin-left: 0;
        /* transform: translateX(0); */
    }
}

.wrapper {
    width: 400px;
    animation-duration: 3s;
    animation-name: slide;
    animation-iteration-count: infinite;
    display: flex;
    flex-wrap: wrap;
    background: rosybrown;
}

.item {
    width: 20px;
    height: 20px;
    line-height: 20px;
    text-align: center;
    border: 1px solid #aaa;
}
